Some people asked what I meant by a “toolkit architecture” in the previous post about my middleware fears. It turns out I wrote about that in a previous Inner Product column that for some reason I never reposted here. I think at the time I wrote this (late 2008), I already wasn’t very concerned about writing reusable code, and I was focusing it mostly with respect to using other people’s code and how I wanted it to be architected. ...
There has been a lot of recent discussion (and criticism) on Data Oriented Design recently. I want to address some of the issues that have been raised, but before that, I’ll start with this reprint from my most recent Game Developer Magazine. If you have any questions you’d like addressed, add write a comment and I’ll try to answer everything I can. Last year I wrote about the basics of Data-Oriented Design (see the September 2009 issue of Game Developer). In the time since that article, Data-Oriented Design has gained a lot of traction in game development and many of teams are thinking in terms of data for some of the more performance-critical systems. ...
One of the more frequent questions I receive is what kind of memory allocation strategy I use in my games. The quick answer is none (at least frame to frame, I do some allocation at the beginning of each level on a stack-based allocator). This reprint of one of my Inner Product column covers quite well how I feel about memory allocation. We’ve all had things nagging us in the back of our minds. They’re nothing we have to worry about this very instant, just something we need to do sometime in the future. Maybe that’s changing those worn tires in the car, or making an appointment with the dentist about that tooth that has been bugging you on and off. ...
In a previous article we covered all the details necessary to start using unit testing on a real-world project. That was enough knowledge to get started and tackle just about any codebase. Eventually you might have found yourself doing a lot of typing, writing redundant tests, or having a frustrating time interfacing with some libraries and still trying to write unit tests. Mock objects are the final piece in your toolkit that allow you to test like a pro in just about any codebase. ...
It’s one thing to see someone drive a car and have a theoretical understanding of what the pedals do and how to change gears. It’s is a completely different thing to be able to drive a car safely on the street. There are some activities that require many small details and some hands-on experience to be able to execute them successfully. The good news is that unit testing is a lot simpler than driving a standard shift, but there are a lot of small details you need to get right to do it successfully. Even after reading about unit testing and being convinced of its benefits, programmers are often not sure how to get started. This month’s column is not going to try to convince you of the many benefits of unit testing (I hope you are already convinced), but rather, describe some very concrete tips to help you get started right away. ...
_I’ve been meaning to put up the rest of the Inner Product columns I wrote for Game Developer Magazine, but I wasn’t finding the time. With all the recent discussion on data-oriented design, I figured it was time to dust some of them off. This was one of the first columns I wrote. At first glance it might seem a completely introductory topic, not worth spending that much time on it. After all, all experience programmers know about pointers and indices, right? True, but I don’t think all programmers really take the time to think about the advantages and disadvantages of each approach, and how it affects architecture decisions, data organization, and memory traversal. ...
Picture this: Toward the end of the development cycle, your game crawls, but you don’t see any obvious hotspots in the profiler. The culprit? Random memory access patterns and constant cache misses. In an attempt to improve performance, you try to parallelize parts of the code, but it takes heroic efforts, and, in the end, you barely get much of a speed-up due to all the synchronization you had to add. To top it off, the code is so complex that fixing bugs creates more problems, and the thought of adding new features is discarded right away. Sound familiar? ...
Have you ever given some thought to why you decided to become a game programmer? I’m pretty sure it wasn’t to do mundane, repetitive tasks. Yet sometimes we find ourselves spending a significant portion of our time making sure that the code compiles for all platforms, or that there are no potential bugs lurking in the depths of the game, or even building the assets for each level and running them to make sure they load correctly. Clearly, those are all things that need to be done, but if they are so repetitive and mindless, couldn’t we put some of the computers around us to good use and have them do the job for us? A build server will do all that and more, much faster and more reliably than we could, and it will free us to work on the thing that made us fall in love with this industry in the first place: the game. ...
I really enjoy a good cup of tea. On the surface, making tea is really easy: take some tea leaves, pour some hot water over them, and wait a few minutes. In practice, the difference between a bitter, undrinkable brew, and a perfect cup of tea is all in the details; the type and amount of tea, the temperature of the water, and the steeping, time all make a huge difference. A playback system for a game is very much the same. As we saw last month, the basic idea is really simple: Record all game inputs, make the game deterministic, and you get the same playback every time. Unfortunately things aren’t quite that simple in real life. Just as with tea making, the secret to a perfect playback system is all in the details. ...
Insanity: doing the same thing over and over again and expecting different results. – (attributed) Albert Einstein How would you like to be able to reproduce every crash report that QA adds to the bug database quickly and reliably? How useful would it be to be able to put a breakpoint the frame before a crash bug happens? You can do all that and more if your game is deterministic and you feed it the same inputs as an earlier run. Sounds easy? It is, if you implement it early on and you keep it that way during development. If you choose not to make your game deterministic, your team will go insane by Einstein’s definition, and maybe by a few other definitions as well by the time the project ends. ...